When you are doing your girlfriend in the ass, before the man cums he holds it in and spits on his girlfriends back making her think he came, then when she turns around the man cums on her face and yells "Spiderman'd!!!"

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

To ejaculate into ones hand and then fling semen at one's enemies as a defense mechanism